As the threat of terrorism increases, the need to identify suspicious activities is very important. However, the identification of these activities can be very difficult. For example, the purchase of fertilizer does not on its face appear suspicious, but this fertilizer could be used to build a bomb. Thus, it is difficult to identify data of interest in criminal and homeland security investigations because each of the pieces by themselves may appear innocuous, but when the pieces are all put together they may reveal a terrorist plot.
For example, in the recent London attacks a large amount of pure hydrogen peroxide, a large industrial refrigerator and heat tags were purchased. Each of these purchases might be slightly suspicious, or not all, by themselves, but together, if known, may set off flags as being highly suspicious as all of the things that were purchased were purchased within a defined location in close time proximity. This information, even if entered into a database environment, may not stand out as suspicious because this information is difficult to analyze and the recognition of a pattern that would set off a flag may require both experience and intuition, which a computer database does not typically have. One example of an existing criminal database is International Business Machine's Criminal Information Warehouse (CIW). CIW is a large scale database which includes information on criminals, potential criminals, persons of interest and the like.